Conclusion – external threat and internal divisions: How the war in Ukraine shapes mass politics in the EU

Abstract

I review this Special Section in three steps. First, I summarize the theoretical framework, contrasting bellicist and polity-maintenance perspectives on how outside threats such as the war in Ukraine affect the mass politics of EU integration. Second, I report findings about public attitudes and party positions on the war and the EU's reactions to it. The articles show a broad permissive consensus on more policy integration, and a modest ‘Europeanization’ of party-political messaging. Third, I compare findings on four major explanatory variables: threat perceptions, country-level differences, individual identity and political ideology. The articles show a unifying effect of the war on European mass publics. The remaining disunity is mostly within, not between member states. I conclude with some speculative notes on the future of European unity.

A moment of unity

How did the Russian invasion of Ukraine in 2022 affect mass politics in the European Union? Did it shape public opinion on the EU? Did it change party positions? Did it trigger support for more policy coordination and centralization? The contributions to this Special Section argue that the war had a major impact. It fueled public demand for more common EU policy-making. It led political parties to Europeanize their political messaging. It forced the populist right to tone down its pro-Russian rhetoric. The overall message is upbeat. The war has instilled Europe with a new sense of unity and purpose: “political pressure is low, and conditions are ripe for elites to push integration forward” (Moise and Wang, 2025b). After years of hand-wringing over postfunctionalism, constraining dissensus and the imminent threat of disintegration, the Russian invasion gave new thrust to integration.

In this concluding note, I review the findings of this Special Section in three steps. First, I comment on the theoretical framework, comparing bellicist and polity-maintenance perspectives on the mass politics of integration. Second, I report what the articles tell us about public attitudes and party positions on the war and the EU's reactions to it. Third, I compare findings on four major explanatory variables: threat perceptions, country-level differences, individual identity and political ideology. I conclude with some speculative notes on the future of European unity.

Two logics of integration: Bellicist and polity maintenance

Moise and Wang set the frame for the special issue in their introductory article (2025a, 2025b). They argue that the Russian invasion of Ukraine presents a “most-likely case for transformations in public attitudes and party positions” for two main reasons. First, the scale and proximity of the Russian aggression is likely to trigger a threat-based “bellicist” logic of European community building, and second, the uneven, asymmetric vulnerability of individual EU member states and citizens is likely to trigger a solidarity-based logic of “polity maintenance”. The former logic highlights that the Russian threat affects the EU as a whole, the latter that the threat affects different states and citizens of the EU differently.

The “bellicist” logic is a staple in the state-building literature (e.g., Besley and Persson, 2011; Riker, 1964; Tilly, 1992) that has recently been applied to European integration (Genschel and Schimmelfennig, 2022; Kelemen and McNamara, 2022; Moise et al., 2024). It posits that military threats induce a sense of community among the threatened. A threat gives the threatened a common cause of worry and a common purpose to rally around. The collective need to cope aligns interests, and mutes conflict within and across member states. It creates feelings of togetherness, solidarity, and shared fate that provide a permissive consensus “to centralize a policy in order to meet the immediate threat (e.g., a centralized army that is necessary to fend off aggressors)” (Moise et al., 2025). Outside pressure increases inside cohesion.

The “polity maintenance” logic starts from the opposite assumption. It assumes that the primary effect of outside pressure is to corrode inside cohesion. The political and social cohesion of the EU is fragile and contested in the best of times (Ferrera et al. 2024). External threats weaken it further by exposing the member states to asymmetric pressures that lay bare old and create new fault lines within and between national societies (Ferrara and Kriesi, 2021). Yet, the threat-induced risk of disintegration and fragmentation is not necessarily passively endured but can trigger active counter reactions. Political elites mobilize for, and mass publics accept, more policy coordination and centralization to “maintain unity among sub-units (e.g., providing compensation to MS who face higher costs from refugees [from Ukraine] or sanctions [on Russia]” (Moise et al., 2025).

While the bellicist logic suggests a “direct” causal pathway from the Russian threat to enhanced EU integration, the polity-maintenance pathway is “indirect”: from the Russian threat, to asymmetric effects on the member states, to reduced social and political cohesion in the EU, to more integration to regain cohesion (Moise et al., 2025). Surprisingly, the articles of this Special Section make little effort to identify both pathways empirically and compare their relative contribution to integration outcomes. The main focus is on the bellicist logic: did the onset of the war affect the demand and supply of integration? Individual and country level heterogeneity is introduced as a conditioning factor. This is an interesting perspective but sheds little light on whether it is primarily the Russian threat or the fear of EU-disintegration that drives changes in demand and supply conditions.

Demand and supply of integration

The main interest of this Special Section is to map and explain the demand and supply of integration in the mass-politics arena. In the articles, ‘demand’ refers to public attitudes towards more policy centralization and coordination in the EU. ‘Supply’ refers to party positioning on EU integration and policy (Moise and Wang, 2025b). The focus on the mass politics arena reflects the high salience of the Russian aggression in Ukraine and of Europe's policy reactions to it. Under conditions of high salience, public attitudes are an important constraint and a potentially powerful driver of integration, and the reactions of political parties are a main determinant of the responsiveness of the political system (Hooghe and Marks, 2009).

Three articles focus on the demand side. Moise et al. (2025) explore public attitudes towards policy centralization in four policy areas that are strongly affected by the war: refugees, energy, cost of living, and defense. They use a conjoint experiment to explore whether and when respondents prefer separate national or coordinated EU policy-making in these areas. Their findings show a broad consensus for EU-level refugee burden-sharing. Support for EU policy-making in the other policy fields is less pronounced and more contested. The experiment was fielded in five EU member states (France, Germany, Hungary, Italy, Poland) in December 2022.

Moise and Wang (2025a) analyze public attitudes to appeasing Russia or standing by Ukraine. Should Ukraine give up territory to end the war? Should the EU and the US curtail support for Ukraine? Should they stop NATO enlargement to Finland and Sweden? Do Western arms deliveries to Ukraine do more harm than good? The findings show majority support for standing by Ukraine, but also considerable variation across and within member states. They also show, however, that appeasement becomes more popular as the perception of the Russian threat intensifies. The study is based on a two-wave panel survey in France, Germany, Hungary, Italy, and Poland in July and December 2022.

Oana et al. (2025) look into public attitudes towards EU energy policy. More specifically, they analyze support for energy sanctions against Russia, and for allocating the attendant costs to individual citizens, national governments, or the EU. They find consistent support for energy sanctions, again subject to some variation within and between member states. Yet, they don’t find a clear preference for EU-level cost sharing. As long as the costs don’t fall on individual energy consumers, respondents are indifferent between national or EU-level cost sharing. The study is based on a factorial vignette experiment in France, Germany, Hungary, Italy, Poland, and Portugal in July 2022.

Overall, the three contributions paint a fairly benign picture of the demand side of integration. The findings suggest a broad permissive consensus on more integration in a wide range of policy fields. Dissent is relatively rare and subdued. This should afford political elites with the leg space and the incentives to supply more integration. Do political parties use this opportunity? Do they advocate more policy coordination and centralization? Two articles analyze the supply side of integration.

Sojka et al. (2025) analyze official Facebook posts of a very large sample of political parties throughout the EU. The aim is to see whether explicit references to EU institutions, leaders, and policies increased in response to the war: did European political parties contribute to a “vertical Europeanization of domestic political debates” in the wake of the Russian invasion? (Sojka et al., 2025) The findings suggest that they did. EU references in party posts on Facebook generally increased after February 2022. However, the size of the increase is small compared to the huge increase in vertical Europeanization during the European election of 2019. Also, there is considerable variance across parties and member states. Data comes from a novel dataset containing all Facebook posts published by 275 national political parties in the 27 EU member states, 2019 to 2023.

Finally, Wang and Altiparmakis (2025) explore how right-wing populist parties adapted their political messaging on Russia after the start of the war, again focusing on official posts on Facebook. As they show, right-wing parties toned down their pro-Russia rhetoric but didn’t completely disown it. Their main reaction was obfuscation: party posts strategically blurred issues and responsibilities, and shifted the blame for attendant problems to the EU. The populist right is less openly pro-Russia than before but still a long way from offering active support for an effective EU response to Russian aggression. The article is based on an original dataset of official Facebook posts of eleven right-wing parties from different member states, 2013 to 2023.

In sum, the two supply-side articles show a repositioning of parties in response to the war. However, the size of the change is small relative to the size of the challenge, and it is purely rhetorical. It is unclear whether increased references to the EU in official party messaging “necessarily translate into more support for European integration” (Sojka et al., 2025) ¹ . The “question remains as to whether elites would be incentivized to do so” (Moise and Wang, 2025b). In short, the Special Section has more to say on the demand-side than on the supply-side of integration. It is good at mapping what mass publics want but less good at showing whether and when these wants matter for elite decisions on policy coordination and centralization.

Threat, symmetry, identity, and ideology

The contributions to this Special Section focus on four explanatory variables to account for variance in the demand and supply of integration: the perceived level of the Russian threat, asymmetric exposure to the threat at the country-level, and different identity concepts and political ideologies at the individual level. I briefly summarize the main findings.

Threat is the key variable of bellicist theories. The articles broadly support the idea that external threats fuel policy integration and coordination but with some caveats. The onset of the Russian invasion triggered a perceptible increase in public demands for integration. As Oana et al. (2025) show, the Russian aggression is associated with robust support for energy sanctions on average. If presented a high-escalation scenario, respondents modestly increase this support compared to low-escalation scenarios. Yet, as Moise and colleagues show, the threat-induced demand for policy integration varies by policy area: demand is highest for refugee policy, presumably because the influx of refugees from Ukraine is a highly visible and immediate impact of the war. Demand is fairly low in defence, arguably because responsibility for defence is attributed mainly to NATO and not the EU (Moise et al., 2025). There is also evidence of supply-side reactions to the onset of the war: parties Europeanized their political messaging (Sojka et al., 2025) and blurred their previous affinities to the Russian government (Wang and Altiparmakis, 2025). However, as Moise and Wang (2025a) show, higher levels of threat-induced intra-EU cohesion and solidarity do not automatically translate into higher levels of solidarity with Ukraine. To the contrary, higher threat is associated with higher demand for appeasement.

Asymmetric vulnerabilities at the country level condition the EU's response to the Russian threat. Asymmetries can either moderate the bellicist thrust towards policy centralization by causing disagreement over whether and what to centralize, or they can fuel a polity-maintenance induced drive towards centralization to protect the unity and cohesion of the EU. The articles consider country-level differences in terms of geographical proximity to Russia and/ or Ukraine (Moise et al., 2025; Oana et al., 2025; Sojka et al., 2025), fiscal strength (Moise et al., 2025; Oana et al., 2025), military capacity (Moise et al., 2025), and economic or energy vulnerability (Moise and Wang, 2025a; Oana et al., 2025). Yet, effects are modest. Country differences notwithstanding, the articles find a broad, cross-country consensus on the desirability of a common refugee policy (Moise et al., 2025), energy sanctions (Oana et al., 2025), and continued support to Ukraine (Moise and Wang, 2025a). Disagreements are partial and selective such as the Polish preference for defence nationalism over a common EU defence fund (Moise et al., 2025) or the Hungarian opposition to energy sanctions (Oana et al., 2025). In short, country heterogeneity has not prevented considerable cross-national unity in public attitudes towards EU responses to the war. Most disunity is within, not between member states (see also Hooghe et al., 2024).

Identity and political ideology are important drivers of within-country disunity. The effect of identity is straight-forward: a European sense of identity tends to increase support for common EU responses to the war, and reduce support for appeasement while a national identity works in the opposite direction (Moise et al., 2025; Moise and Wang, 2025a; Oana et al., 2025). The impact of ideology is more complex. On the one hand, attachment to the populist right is associated with a comparatively strong preference for national policy solutions (Moise et al., 2025), for appeasement (Moise and Wang, 2025a), and against energy sanctions (Oana et al., 2025). Right-wing parties hardly increased the number of EU references in their Facebook posts after the onset of the war while parties on the left increased them markedly (Sojka et al., 2025). On the other hand, a relative preference for national solutions doesn’t prevent support for policy centralization on specific issues. For instance, self-identified rightist respondents support, on average, a centralized EU refugee-sharing scheme (Moise et al., 2025) or energy sanctions on Russia (Oana et al., 2025) even though the level of support is lower than from leftist or centrist respondents. Also, right-wing populist parties made concessions in their political messaging to an increasingly Russia-critical mainstream (Sojka et al., 2025; Wang and Altiparmakis, 2025). Finally, rightist positions are not always consistent. Perhaps most prominently, the Polish PiS party is staunchly anti-Russian in contrast to most of its peers from other member states (Moise and Wang, 2025a). The war increased the salience of this intra-right disagreement.

In short, the evidence suggests that the Russian threat had a unifying effect on European mass publics in line with the bellicist logic. Country-level heterogeneities mattered relatively little. Disagreement on the desirability of integration was mostly within member states between voters of different identity and political ideology. Yet, even here Eurosceptic positions came under pressure, facilitating the emergence of a permissive consensus, and pro-integration coalition formation.

Will the unity last?

All empirical research is historical. Most data for this Special Section are from fall 2022. By academic standards, this is very recent. Yet, in a quickly changing environment, data may age quite quickly. It is a crucial question, therefore, whether the relatively benign findings still hold. Following the Special Section's main arguments, the answer should depend on three factors: change in perceptions of the Russian threat, change in the salience of country-level heterogeneity, and change in the adjustment pressure on right-wing parties.

Consider change in threat perceptions first. At the time of writing (November 2024), the war is well into its third year. Still, it hasn’t spread to other countries, let alone to EU member states. Hostilities remain localized inside Ukraine, so far. The longer the territorial containment of the conflict lasts, the more likely it becomes that EU mass publics downgrade the Russian threat. A threat that was clearly perceived as a “European issue” (Sojka et al., 2025) in 2022 shrivels to mostly a Ukrainian issue today. As the threat loses immediacy, the bellicist demand for more policy centralization and coordination slackens. The apparent ineffectiveness of Western assistance to Ukraine further undermines public support. The EU swiftly imposed a string of far-reaching sanctions in 2022. Yet, the sanctions failed so far, to visibly dent the Russian economy, let alone stop the Russian war effort. The West supplied Ukraine with weapons of increasing lethality. Still, the fortunes of war have shifted in Russia's favour. Remarkable Ukrainian military gains in 2022, gave way to stalemate in 2023, and increasing difficulties to hold the line in 2024. Obviously, the war is unpredictable. A reversal of fortunes is always possible. The pendulum could swing back in Ukraine's favour. As long as it doesn’t, however, the Russian threat appears not only localized but also intractable for EU policy. Mass publics may tire of the issue and of Europe's involvement in it. Why waste time and effort on helping Ukraine win a war that is not ‘our’ war and apparently unwinnable? The question may sound wrong and deplorable but that does not prevent it from being asked. Bellicism can run out of steam.

Turn to country heterogeneity next. As the immediacy of the Russian threat recedes, the salience of internal conflicts among member states is likely to grow. Uncertainty about the future of NATO may fuel these conflicts further. NATO greatly facilitated EU unity immediately after the Russian attack because it provided a tested framework for joint force mobilization, and an obvious way to keep the US involved in European security. Since there wasn’t any alternative to NATO, the EU quickly deferred to it, and put its own projects for defence integration on the backburner (Genschel, 2022). The US election of November 2024 raised doubts about the tenability of this strategy. Donald Trump has repeatedly questioned the strategic rationale of NATO, and indicated a willingness to disengage, partially or completely. This would leave the EU member states on their own in security to an extent not experienced since World War II. The effect could be ambiguous. On the one hand, it could reinforce the bellicist thrust towards more European integration: a European Defence Union to fill the void left by NATO, joint procurement and stockpiling to strengthen joint energy independence, more financial solidarity to spread the fiscal burden of defence more evenly. The EU stronger together! On the other hand, the build-up of solid and operational EU structures for defence and related policies would take time, and success in terms of security and effectiveness would not be guaranteed (Genschel, 2022). This uncertainty may fuel policy nationalism, rather than integration (Moise et al., 2024). As Hoffmann (1966: 882) observed long ago: “in areas of key importance to the national interest, nations prefer the certainty, or the self-controlled uncertainty, of national self -reliance, to the uncontrolled uncertainty of the untested blender”. In the absence of durable and effective EU structures, some member states like Germany and Poland may seek bilateral defence deals with the US (or the UK) even if that hinders European defence integration further. Others like France or Spain may seek European solutions even at the risk of antagonizing the US further. The Atlanticist – Gaullist split would open again, triggering disagreement and strife.

Finally, the pro-Russian ideas that “Putin's friends” in European party politics were eager to blur in 2022 (Wang and Altiparmakis, 2025), may re-emerge and gain respectability as pro-peace ideas. This is partly due to the electoral gains of right-wing parties in national elections since 2022 and in the European elections of 2024. As the populist right increases its vote share, the pressure to adjust to mainstream positions may relax because far-right positions are increasingly mainstream. The moderating incumbency effect (Hooghe et al., 2024) weakens as incumbents radicalize. Partly, it is because the US elections have shifted the coordinates of what it means to be ‘realistic’ about the war. As long as Joe Biden was in power, realism meant to shift the blame for the war on Russia, to offer support to Ukraine as long as it takes, and to commit to Ukraine's eventual membership in NATO and the EU. After the election with Trump's emphasis on ending the war quickly, realism means being sceptical about Ukraine's ability to win the war, and accepting the need for Ukrainian concessions both in terms of ceding territory and foregoing NATO membership. Without any active contribution on their part, the discourse moves towards the positions of Russophile right-wing parties. They have to blur their position less, while mainstream parties may have to start blurring theirs.

In conclusion, it is easy to doubt that the Special Section's optimism about European unity and integration is still justified. The “window of opportunity for further polity formation” (Moise et al., 2025) that the Russian aggression had pushed open in 2022, may be closing again. Why has it not been used better? These articles have little to say on this because they focus on the demand and hardly touch the supply of integration. Integration is not just a matter of party politics but also of interest groups, governments, supranational agents, and all the other elite actors that were at the core of EU theorizing before Postfunctionalism directed attention to the mass politics of integration. Incidentally, the Special Section demonstrates not only the potential of a mass politics approach to integration theory but also its limits. It can explain the structure of the constraining dissensus or permissive consensus within and across member states but it cannot explain how political decision makers react to this structure and turn it into integration outcomes.

Even if the EU should have missed its moment of unity, this is not the end of the story. As the polity-maintenance paradigm highlights, integration can also follow from disunity (Ferrera et al., 2024). There is not just Tilly and Milward (Moise et al., 2024). There is also Hölderlin ² : “Wo aber Gefahr ist, wächst das Rettende auch” (roughly: Where there is danger, the rescue grows as well).